Seasonality effect is the abnormal returns connected with the calendar. The existence of the seasonality is a strong challenge to the Efficient Market Hypothesis (EMH).

季节效应是指与季节相联系的股市非正常收益，由于它在很大程度上违背了市场有效性的假说，因此对季节效应的研究一直备受国内外金融市场的投资者和管理者的关注。

An established formula of seasonality rectification could eliminate the seasonal effect on the facial skin elasticity. The healthy female facial skin in Guangzhou city changed with the seasonal variation.

结论:以皮肤弹性指标的化妆品功效试验或美容激光等治疗疗效的评估要考虑季节因素对皮肤弹性数值的影响;建立的季节性校正公式可以消除季节对面部皮肤弹性数值的影响。